Hak, Ishak. “THE EFFECTIVENESS OF COOPERATIVE LEARNING NUMBER HEAD TOGETHER IN ENGLISH SUBJECT IN JUNIOR HIGH SCHOOL”. Jurnal Inovasi Pendidikan Dan Pengajaran (JIPP), vol. 1, no. 3, Dec. 2022, pp. 134-4, https://journal.ikippgriptk.ac.id/index.php/JIPP/article/view/4636.